1. Field of the Invention
The present invention relates to a solid drawing material and, particularly, to a solid drawing material which features particularly smooth draw feeling, and is not easily collapsed and is not easily broken, either.
2. Description of the Related Art
A crayon which uses wax like paraffin as a solidifying agent is accompanied by such defects that it cannot provide a flat surface of application, involves difficulty when it is attempted to apply it to wide areas, does not permit the applied surface to be cured which, therefore, is prone to be contaminated and discolored and, further, makes it difficult to apply another crayon thereon since the applied surface becomes slippery. A pastel, on the other hand, contains neither wax nor oil and comes in a sticky form by solidifying a powder of pigment or the like with a water-soluble adhesive component of a low concentration. However, the pastel cannot be fixed onto a paper. Therefore, a color must be fixed by spraying a special fixing solution onto the drawing surface. Besides, the pastel has another defect in that the powder thereof scatters to foul the surrounding.
In order to improve the above defects, solid drawing materials in the form of aqueous gel sticks have been proposed by using an alkali metal salt or an ammonium salt of an aliphatic carboxylic acid as a gelling agent (see patent document 1, patent document 2 and patent document 3).
[Patent document 1] JP-A-1-217090
[Patent document 2] JP-A-4-337372
[Patent document 3] JP-A-5-311107
When compared to the wax-type crayon, however, the solid drawing materials disclosed in the above patent documents 1 to 3 are weak, and are subject to be collapsed and broken during the use. The hardness can be increased to some extent by increasing the ratio of blending a soap such as an alkali metal salt causing, however, a decrease in the flexibility of a stick which, therefore, becomes rather subject to be broken. Besides, smooth draw feeling is impaired and shavings are produced much while drawing. Moreover, fluidity of the sol so decreases that it becomes difficult to execute the molding for production.